The State Department revealed Friday it has been quietly offering a $10 million reward to help track down the militants behind last year's deadly attack on a US mission in Libya.
The brazen assault in Benghazi cost the lives of four Americans, including ambassador Chris Stevens, with the fatalities and disputes about what unfolded at the diplomatic base causing fury in Washington.
A State Department spokesman told AFP that its Rewards for Justice program has since January been offering up to $10 million "for information leading to the arrest or conviction of anyone who was involved in the September 2012 Benghazi attacks."
The reward was not widely publicized when it was first made available, because of what the Department called "security issues and sensitivities surrounding the investigation."
"Since this event happened... we've made it clear that we are committed to bringing the people who conducted this attack to justice. And we're using all the appropriate tools we have to do that," the spokesman said.
The reward on offer "was for anyone who was involved, not for any particular individual," added the official, who asked not to be named.
Hordes of heavily armed militants stormed the mission on September 11 last year and then attacked a nearby CIA compound with mortar shells and rockets.
Ambassador Stevens was killed in the hours-long firestorm along with three other diplomatic and security staff -- Sean Smith, Glen Doherty and Tyrone Woods.
Stevens, a popular diplomat and fluent Arabic speaker, was the first US ambassador to be killed while on duty in three decades, and the assault shocked America and the close-knit diplomatic family.
Initially, the sacking of the mission was described by American officials as having been triggered by an anti-Muslim video aired in the United States which sparked protests across the Arab world.
Signup to our newsletter and follow us on Facebook and Twitter!
But it was later revealed that some of those behind the assault had links to organized Al-Qaeda extremists.
So far no-one has been charged or arrested in the US investigation which is being led by the FBI. The Libyan authorities are carrying out a separate probe.
The event roiled the 2012 US election race, with Republicans using it to hammer Democratic President Barack Obama and his administration as being lax on security just weeks before November polls that he won.
To this day, many Republicans insist there was a conspiracy by the Obama administration to cover up what really happened in Benghazi.
A State Department internal probe slammed "woefully inadequate" security arrangements, and set up a series of recommendations to ensure missions are better protected.
But the issue has refused to die down, and lawmakers recently quizzed the State Department about what moves were being taken to bring those behind the attack to justice.
The confirmation of the reward came in Secretary of State John Kerry's reply to a letter from Homeland Security Committee chairman Michael McCaul, signed by 82 other lawmakers.
"Because of recent public attention we felt the need to address the issue," the State Department official told AFP, referring to clamor in the media and Congress.
Since its launch in 1984, the Rewards for Justice program run by the Diplomatic Security bureau of the State Department has paid out $125 million to some 80 people for information leading to the capture of terrorists.
Despite the dangers of tipping off American intelligence agencies, the rewards can be tantalizingly huge in impoverished countries. One informant earned $30 million for leading the US to Uday and Qusay Hussein, the sons of late Iraqi dictator Saddam Hussein, who were tracked down in July 2003.
Anyone with information on the Benghazi attacks can visit the program's website www.rewardsforjudstice.net.